(Well, let's just start to lean more into it, make it seem as the story is going full without plot holes, is what I'd say is the best course of action.)
There was a vent situated closely to above Raz, and as he slept, his body gave off a subtle heat and a pleasant smell, the smell of a campfire, that rose through the vents and leaked into Luka's room while she slept, and the rest of the upper floor rooms, but no smoke was formed, there was only the smell.